Isner digs deep to progress in soggy Shanghai
John Isner of the US hits a return to Santiago Giraldo of Colombia in their first round match of the Shanghai Masters tennis tournament in Shanghai on October 7, 2013
The 14th seed dodged heavy rain and swirling winds by playing under the closed roof at the Qizhong tennis centre, taking time to impose his heavy-serving game on his 83rd-ranked opponent before he eventually emerged on top.
It was one of just four first-round matches played on day two of the tournament as the bad weather played havoc with the schedule, with veteran 11th seed Tommy Haas and Frenchman Gael Monfils among the other winners.
The six foot 10 inch (2.08 metres) Isner -- America's top player -- lost the first set 6-4, but dug deep to win the second 7-5, levelling the match on his seventh set point.
Isner, who fired down 29 aces but made 32 unforced errors, broke Giraldo in the 12th game of the decider to take it 7-5.
He admitted afterwards that he had expected a tricky match.
"I started off a little slow in the first set. I told myself the only thing I could do was keep fighting. I felt like I was serving well, so just tried to hold serve as best as I could. That's what I did," he said.
"It took me a little while to break through in the second set, but I was able to. I think it was an accumulation of I was putting a lot of pressure on his serve really throughout the whole match. I feel like I had a lot of love-30s, a lot of breakpoints."
Germany's Haas was untroubled by America's Sam Querrey, easing to a 6-4, 6-4 win, while Monfils made short work of Japanese qualifier Tatsuma Ito, seeing him off 6-3, 6-2.
Earlier, Spain's Marcel Granollers was a straight-sets winner over an out-of-sorts Serbian Janko Tipsarevic, who required attention from the physio for an apparent left ankle problem.
Fifth seed Roger Federer, who along with the other top-eight seeds has a bye into the second round, on Monday teamed up in the doubles with China's Zhang Ze, who has a singles ranking of 271, cruising into the second round.
The Swiss 17-time Grand Slam winner, who has slipped to seventh in the singles rankings, is in danger of missing out on next month's end-of-season ATP World Tour Finals, currently held in London, for the first time since 2001.
He faces a potential quarter-final meeting with defending champion and top seed Novak Djokovic, who has dropped one place to world number two behind Rafael Nadal, despite beating the Spaniard in the China Open final at the weekend.
Typhoon Fitow slammed into China's east coast early Monday, packing winds of more than 200 kilometres (124 miles) an hour, killing at least five people and impacting three million, state media reported.